Maskless Exposure Die Shift Correction via Pre-Scanning
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Solution Overview
Problem
In photolithography, die shift errors during bonding lead to misalignment of conductive contact portions with contact holes, causing connection issues, and existing solutions like enlarging contact holes compromise structural strength, while real-time focal adjustment in maskless exposure machines is hindered by slow distance measurement and focal length changes.
Innovation Solution
A die shift correction method that calculates compensation sections based on die shape and location to align exposure patterns with contact holes, using pre-scanning to capture state and elevation information for precise light exposure, and adjusts focal length in real-time using a laser rangefinder to maintain focused exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the area of each substrate contact hole is enlarged to accommodate die shift errors, then the alignment tolerance is improved, but the structural strength of the substrate deteriorates
Solution Approach 1:
The patent performs pre-scanning of the die position and shape before the actual exposure process. By measuring the die's actual position and orientation in advance, the system calculates compensation sections that adjust the exposure pattern to match the die's actual state, thereby correcting alignment errors without needing to enlarge contact holes
Solution Approach 2:
The patent dynamically adjusts exposure parameters based on measured die characteristics. The system changes the exposure pattern's position, shape, and orientation parameters according to the pre-scanned die state, allowing precise alignment adaptation without physical modification of the substrate contact holes
2Manufacturing precision
If real-time focal length adjustment is implemented to correct die warping, then the focus precision is improved, but the response time deteriorates due to slow distance measurement and focal length change
Solution Approach 1:
The patent performs distance measurement and focal length adjustment before the exposure process begins. By pre-measuring the die's elevation information and pre-adjusting the focal length, the system eliminates the need for slow real-time adjustments during exposure, thus maintaining focus precision without sacrificing response time
Solution Approach 2:
The patent separates the focus adjustment process into distinct phases: pre-measurement of die elevation, calculation of required focal length, and actual adjustment execution. This segmentation allows the system to perform adjustments efficiently without interfering with the high-speed exposure process
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures accurate alignment and reduced line widths of conductive contact portions, enhancing product yield by correcting die shifts and maintaining structural integrity of the substrate.
Implementation Method 1
obtaining the elevation information of the die by a second pre-scanning means; inputting the elevation information of the die into the maskless exposure machine
Implementation Method 2
adjusts focal length in real-time using a laser rangefinder to maintain focused exposure
Data Source
AI summary
A die shift correction method for use by a maskless exposure machine is applied to a die bonded to a substrate. The substrate has plural contact holes. The die has plural contact points each intended to be subjected to a light exposure in order to form a conductive contact portion connected to the corresponding contact hole. The correction method includes: obtaining the state information of the die by a first pre-scanning means, wherein the state information includes shape and location information; comparing the state information of the die against a reference state, and calculating compensation values with which to correct the reference state and thereby bring the reference state into conformity to the state information of the die; and calculating a compensation section for the light exposure according to the compensation values in order for each conductive contact portion to have an exposure pattern formed at the corresponding contact hole.